In general, there is known a substrate processing apparatus configured to process a substrate (wafer) by vaporizing a processing liquid. An example of such a substrate processing apparatus may be an apparatus configured to perform a coupling processing. That is, to improve adhesivity and flatness of a metal film formed on the substrate by electroless plating, the coupling processing using a coupling agent (processing liquid) such as a silane coupling agent may be performed prior to forming the metal film.
As a substrate processing apparatus which performs the coupling processing, there is known an apparatus configured to vaporize a liquid coupling agent by heating. This substrate processing apparatus includes a processing chamber configured to place a substrate on a hot plate and process the substrate; and a vaporizer and a vacuum pump connected to the processing chamber. The vaporizer is equipped with a heater for vaporizing the coupling agent. With this configuration, as the coupling agent stored in the vaporizer is vaporized by the heater and supplied into the processing chamber by a suction force of the vacuum pump, the substrate within the processing chamber is coupling-processed.
In case of vaporizing the liquid coupling agent by heating, however, the vaporization may not progress sufficiently, so that mist in a liquid phase may be generated. In such a case, the liquid coupling agent may remain in a pipeline through which the coupling agent is supplied into the processing chamber from the vaporizer. If this residual liquid coupling agent is introduced into the processing chamber, it may adhere to the substrate, causing particle generation on the substrate. Furthermore, since the coupling agent remaining in the pipeline may not contribute to the processing of the substrate, a larger amount of the liquid coupling agent is required to vaporize a sufficient amount of the coupling agent. As a consequence, a consumption amount of the coupling agent used in the vaporizer may be increased.
Patent Document 1: Japanese Patent Laid-open Publication No. 2005-008954